Aux air valve shouldn't have much to do with cold starting ..
unless the hoses to it are off or something like that.

----- Original Message -----
From: "pickle vanagon" <greenvanagon@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, June 19, 2011 3:14 PM
Subject: Re: '84 1.9L 2-WD -- cold start problems still the same after new
O2-sensor, new Temp II sensor, and new plugs

> The only other thing that comes to mind is the aux air valve.
>
> This is the little valve that is supposed to be open when the engine is
> cold
> letting in extra air, and then close as it warms up.  It has a plug that
> goes into it as well, that powers a heating element.
>
> The spring in yours might be worn out, or maybe the valve "door" itself is
> gunked up and stuck in place.
>
> I don't think these can be purchased new anymore in the Vanagon part
> number,
> but I think they are interchangeable across old VWs (jettas, busses,
> whatever).  [warning: I'm embarrassed to say that I know from experience
> that it is easy to overtighten the locking nut on the the adjustment screw
> and break off the screw.]
>
>
> But, on the other hand, your aux air valve could be fine, in which case
> this
> is going to add another variable that you'll be fiddling with trying to
> get
> in the right balance with the idle screw setting.
>
> Good luck!
>
> On Sat, Jun 18, 2011 at 12:43 PM, John Lauterbach <
> jhlauterbach@bellsouth.net> wrote:
>
>> Cold start problem definition:  Engine temperature and air temperature
>> around 70-75 degrees Fahrenheit.  Start engine w/o foot on accelerator
>> pedal.  Engine starts and goes to around 800 rpm (instrument panel
>> tachometer).  If slight pressure put on accelerator pedal to take rpm to
>> 1500 or so, and then pedal released, rpm drops to around 300 and engine
>> tried to stall and then picks up speed and then tries to stall.  Slight
>> pressure on accelerator pedal for a couple of minutes or so, solves the
>> problem.
>>
>> Here is what I have done:  New within the past two weeks are new
>> O2-sensor, new Temp II sensor, and new plugs.  A couple of months ago, I
>> put in new rotor and cap.  Timing is just ahead of the mark.  I am also
>> working with backup ECU and I have cleaned the contacts on large cable
>> going into ECU.  I have checked for vacuum leaks and replaced suspect
>> hoses and fittings.
>>
>> Engine is Boston Bob rebuild that I installed in September 2003.  Has
>> about 40,000 km on odometer.  Just about everything I could buy
>> new/rebuilt at that time such as distributor and AFM went was replaced
>> at that time.  A few years ago, I installed a rebuilt throttle body.
>>
>> Recommendations on next steps would be appreciated.
>>
>> John
>>